Thermodynamics Research Center / ThermoML | Journal of Chemical and Engineering Data

ABSTRACT

Liquid-liquid equilibria of formic acid(FA) and furfural in a biphasic aqueous-organic system was studied. 14 kinds of high-boiling and great density difference with water were first screened to measure the distribution coefficient of furfural. Eight solvents with high furfural distribution coefficient were further screened for FA extraction. Six solvents (1,2-dimethoxybenzene, 2,4-dimethyl-1-nitrobenzene, diethyl phthalate, tributyl phosphate, dibutyl phthalate and dibutyl sebacate) with low FA distribution coefficient were then selected to measure the mutual solubilities at 298.15K. Furthermore, two amine extractants (tri-n-octylamine and amine N235) were diluted in six solvents for the extraction of FA and furfural from aqueous solutions to optimizate solvent and extractant. 2,4-Dimethyl-1-nitrobenzene or diethyl phthalate were proven to be more suitable for this system. effects of amine extractant concentration in solvents were evaluated to balance furfural and FA distribution coefficient with little loss of furfural selectivity and significant FA selectivity change, thermal decomposition of FA and furfural in selected solvent+ amine extractant system were then studied. In general, the equilibrium favored the extraction of furfural for 2,4-dimethyl-1-nitrobenzene and the extraction of FA for 2,4-dimethyl-1-nitrobenzene (15wt% amine N235) with little loss of furfural selectivity. 2,4-Dimethyl-1-nitrobenzene containing product were thermally stable enough at 473.15K.